LM2596 circuit voltage regulator and datasheet

Do you want a 3A voltage regulator circuit? Before we often you LM350. But now we may use others. Some use LM2596 circuit.

It is suitable for easy and convenient use as a step-down switching regulator. Some called a buck converter circuit.

LM2596 datasheet

Here are why I like them.

Drives 3.0 A load with excellent line and load regulation.

LM2596 Fixed voltage Regulator 3A

Runs on a switching frequency of 150 kHz. So, we can use a smaller sized filter than lower frequency switching regulators.

Requires a few external components. So, smaller circuit.
Imagine You are using LM350 is smaller and not hot. I like the LM2596.

Features

Let’s read the features. I may say wow!
There are 2 versions. Fixed and Adjustable voltage Read more below

  • Fixed output voltages of 3.3V, 5V, 12V. Requires only 4 external components
  • Adjustable Output Voltage Range 1.23 V − 37 V
  • 3.0A Output Load Current (Guaranteed)
  • Wide Input Voltage Range up to 40 V
  • 150 kHz Fixed Frequency Internal Oscillator
  • TTL Shutdown Capability
  • Low Power Standby Mode, type 80 uA
  • Perfect protection circuit. Thermal Shutdown and Current Limit Protection
  • Internal Loop Compensation

Pinout

We can use them with 2 package.

LM2596 Pinout

  • Standard—5-lead TO-220 package with
    several different lead bend options
  • Small—5-lead TO-263 surface mount package. (Now we often see this

 

LM2596 Fixed voltage regulator

In fixed voltage regulator version. See the circuit above.

We can set output voltage with changing IC follows.

  • LM2596-3.3 for 3.3V output.
  • LM2596-5.0 is 5V output.
  • LM2596-12 is 12V output.

And we should other appropriate components too.

  • C1 should become 330uF (when using LM2596-3.3, LM2596-5.0).
    or 180uF (for LM2596-12)
  • L1 = wire coil inductor, be valuable 33uH (for LM2596-3.3, LM2596-5.0) or 68uH (for LM2596-12)

LM2596 Adjustable Output Voltage Regulator

Now we see most people use LM2596 in adjustable out voltage regulator. It is easy like LM350. See in the circuit below.

LM2596 Adjustable Output Voltage Regulator

Please ensure that the input voltage is higher than the output voltage.
In the general input is 3.2V to 40V. And the output is 1.23V to 35V.

We just only add R1 and R2 to Feed back lead. To control the output voltage.

Vout = VREF{(1+(R2/R1)} where VREF = 1.23V
R1: 1K
R2 = R1{(Vout/VREF)-1}

Parts list

C1: 470uF 50V Electrolytic

C2: 220uF 50V Electrolytic

D1: 5A, 40V Schottky Rectifier, 1N5825

L1: 68uH

R1: 1K, 0.25W 1% resistor

C3: 0.0033uF

You are reading here. You may want to build a good DC Variable power supply, right?

Let’s read below.

DIY LM2596 adjustable voltage switching regulator

Here is DIY LM2596 Adjustable Voltage Regulator Switching Power Supply circuit. The Output adjustable 1.23V to 37V at 3A current.

It is a real circuit in use.

See the circuit diagram below.

DIY LM2596 Adjustable Voltage Switching Regulator

How it works

AC voltage from the transformer gets in the circuit.

Here is the step-by-step process.

1. That AC voltage flows fuse-F1 to protect overload current at the output.

2. Then, AC voltage comes in the Bridge rectifier diodes(D1 through D4)

Some may look familiar: This is Unregulated power supply.

Now AC voltage turns a DC pulse ready

3. Next, Both capacitor C1 and C2 filtered that DC pulse to stable DC voltage better.

  • If you want max output is 37V. You should C1-1000uF 63V. Because DC voltage input is 40V max.
  • But output is 15V. You can use C1: 1000uF 25V. Because input DC voltage is 18V. The voltage AC input is 12V.
  • OR the output is 30V. You can use C1: 1000uF 50V. The AC voltage input is 24V.

If you see: Unregulated power supply principle you more understand.

4. LM2596 get the DC voltage. It keeps a constant voltage in a switching regulator. It needs to have a helper are:

  • L1 is a special inductance, which acts as energy conversion.
    when you look a switching regulator need have it.See: How to make inductance easily!
  • D5 is the Schottky diode, which plays a continuous role in the circuit.Check: you cannot check this type diode in normal use this tool.
  • C5 is Feedforward Capacitor. It keeps a more stable voltage of the circuit. When the output voltage is more 10V up.

5. The output voltage of R1 and W1. We can calculate by the following formula:

Vo=1.23(1 W1/R1)

We notice formula look simar: LM317, LM350 and LM338

6. C3, C4 is the output filter capacitors.

7. LED1 is 8mm white LED. Its brightness can roughly indicate the output voltage.

If the brightness is too bright, you can increase the resistance of R2 properly.

Look… using the limiting current resistor

Parts list

F1- 3A fuse
D1-D4: 1N4007, 1000V 1A diodes
D5: SS34, Schottky diode or 1N5825
C1: 1000uF 50V Electrolytic, See text.
C3: 220uF 50V Electrolytic
C2, C4: 0.1uF 50V Ceramic
C5: 0.0033uF 50V Ceramic
LED1: 8mm white LED
R1: 510 ohms 1%, 0.25W Resistor
VR1: 10K potentiometer
L1: 33 uH coil
R2: see text

What is more

At times, you may wonder like me.
Can use 1N4007 in 3A power supply?
Watch video this circuit can give current more 3A.

Why?

It runs with very high frequency. So, use energy lower and fast. Then, keep the power in the inductor. To reduce a load current of a diode and more parts.

You like this?

If you are interested in this project, do not wait. It is surprisingly cheap. And free shipping Convenient with PayPal payment

Buy here!

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